The overproduction in the body of nitric oxide (NO) and/or peroxynitrite (ONOO.sup.-) has been suggested by some to be a contributing factor to diseases of the central nervous system, particular those that are immune-mediated and/or inflammatory.
The enzyme iNOS is responsible for the production of nitric oxide during an immune response. Nitric oxide combines with superoxide (O.sub.2.sup.-) to form peroxynitrite. Those molecular level considerations are relevant to the present inventions.
An extensively used model system to study multiple sclerosis, an example of a disease treated by the present invention, is experimental allergic encephalomyelitis (EAE) in rats and mice. This model was used for the experiments described below.